Detection and identification of bacterial spp. from culture negative surgical site infection patients using molecular tool

Surgical site infection (SSI) is the most common post operative infections, that sometimes cause postoperative morbidity, mortality and increase in hospital costs. Managing surgical site infections, with negative culture report in routine diagnosis is a common dilemma in microbiology. The present study was carried out to know the presence and frequencies of various bacteria in wound aspirates/ swabs of some culture negative surgical site infection patients attending a tertiary care hospital of eastern India with molecular methods. Ninety seven (97) patients with post-operative SSI whose wound swabs/ aspirate were negative in the conventional aerobic culture after 48 hrs of incubation were taken for finding the presence and identification of any bacteria in sample with 16S rRNA gene specific broad PCR and submitted to NCBI. Of the 97 patients, 16S rRNA based broad range PCR assay could able to identify the presence of bacterial pathogen in 53(54.63%) cases, out of which 29 isolates were of viable but non-culturable bacteria(VBNC), 07 were of obligatory anaerobes and 13 were of unculturable bacteria, 04 were with polybacterial infections. Some measures should be taken in the microbiology laboratory along with conventional culture, for better patient care such as, culture plates should be allowed to incubate for an additional 3 – 4 days that will allow the growth any fastidious bacteria, anaerobic culture system should be developed along with aerobic system, and molecular diagnosis by 16S broad range PCR should be performed routinely.